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Forming Electrical Contacts

IP.com Disclosure Number: IPCOM000090527D
Original Publication Date: 1969-May-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 3 page(s) / 47K

Publishing Venue

IBM

Related People

Ahearn, WE: AUTHOR [+3]

Abstract

This apparatus controls and measures the amount of pressure necessary for the proper contacting of a particular semiconductor device using a double-sided heat sink configuration. After fabrication, an injection laser may lase only in particular places in the junction. Although such diodes usually have filamentary lasing, it is desirable to improve this nonuniformity. For a semiconductor device utilizing a double-sided heat sink configuration, it is desirable to determine the tolerable limits of applied uniaxial pressure during the device fabrication so that proper uniform electrical and thermal contacts can be applied to the device. The uniformity and threshold of lasing can be related directly to the amount of uniaxial pressure applied normal to the plane of the junction.

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Forming Electrical Contacts

This apparatus controls and measures the amount of pressure necessary for the proper contacting of a particular semiconductor device using a double-sided heat sink configuration. After fabrication, an injection laser may lase only in particular places in the junction. Although such diodes usually have filamentary lasing, it is desirable to improve this nonuniformity. For a semiconductor device utilizing a double-sided heat sink configuration, it is desirable to determine the tolerable limits of applied uniaxial pressure during the device fabrication so that proper uniform electrical and thermal contacts can be applied to the device. The uniformity and threshold of lasing can be related directly to the amount of uniaxial pressure applied normal to the plane of the junction. If the uniaxial pressure exceeds a certain limit, nonuniformity of the junction output occurs and device degradation results.

The filamentary behavior of a laser diode is related to poor electrical contact between the heat sink and the laser. The diode is fabricated by placing a laser onto an indium-plated copper heat sink. Another heat sink is placed over the laser. The heat sinks are held in position with an epoxy. The electrical contact is formed before the epoxy is cured and the uniformity of lasing is optimized for any given laser.

Copper heat sink 6, with diode 7 mounted on it, is placed on metal stage 1 which is equipped with heating element 2 and a channel for water cooling 3. The top heat sink 8 of the fabricated device is held in position on metal structure 4 by a vacuum through channels 5.

Heat sink 8 is lowered to make contact with the laser by applying pressure to bar 9. This is coupled to bar 10 by rods 11 which move freely perpendicular to the plane of the junction on the channels in fixed support 12. Stage 1 is mounted on phenolic block 13 to avoid heat loss while the epoxy is being cured. Block 13 is attached to stage 14 of goniometer 15 which provides motion as ind...